I can't come to the rescue and cite the law, but I can say that (as I said earlier) refusal of a request to search is indeed all the probable cause (when coupled to the reasons the officer wanted to do the search e.g. shifty eyes, reefer smell, etc..) that is necessary for a warrant. I work for a police agency - in the five years I've done so not one request has been denied.

In that case, I would expect any evidence gleaned from such a search to be excluded, usually at a prelim, and the case never make it to trial. Granted, it's been 30 since I was a reserve officer, but that much has not changed since then. Any judge signing a warrant because the subject had "shifty eyes" and declined to grant permission to search would wind up getting overturned left and right. PC has to be legitimate and reasonable.
(Sorry if this has already been covered by an LEO or attorney, catching up on thread.)